Lactate elicits vascular endothelial growth factor from macrophages: a possible alternative to hypoxia.

Macrophages respond to various stimuli to produce angiogenic factors but few mechanistic details are known. We examined the effects of hypoxia, lactate and nicotinamide on the expression of vascular endothelial growth factor by cultured macrophages. These agents were chosen because they down-regulate polyadenosine diphosphoribose levels. Following exposure, conditioned media were analyzed for vascular endothelial growth factor protein. Nicotinamide adenine dinucleotide, polyadenosine diphosphoribose, and vascular endothelial growth factor mRNA were measured in the cellular fraction. Angiogenic capacity of the conditioned media was tested in rabbit corneas and Matrigel implants. All three agents, hypoxia, lactate and nicotinamide, elicited significantly increased levels of vascular endothelial growth factor mRNA and vascular endothelial growth factor in the conditioned media, and these levels were paralleled by their angiogenic activity. Polyadenosine diphosphoribose in the cellular fraction was correspondingly depressed. Anti-vascular endothelial growth factor antibody inhibited most of the angiogenic response whereas anti-basic fibroblast growth factor antibody had little effect. We propose that redox changes associated with the alteration of cellular nicotinamide adenine dinucleotide and polyadenosine diphosphoribose are involved in lactate-mediated VEGF expression.

Occult craniocerebral injuries from dog bites in young children.

Although dog bite injuries to the head and scalp of children occur frequently, penetrating dog bite wounds to the cranial vault occur only occasionally and may go unnoticed on initial examination. Substantial morbidity and mortality can ensue if these penetrating injuries are not detected and treated. The authors detail the evaluation of dog bites of the scalp in young children. They highlight the ease with which puncture wounds of the calvarium may be missed during physical examination as a result of scalp displacement at the time of puncture. The cranial puncture may not be large and may later be covered by scalp that returns to its native position. Well-scrutinized skull films and a careful, methodical physical examination are advocated. Recognized craniocerebral injuries should be explored. Depressed cranial fractures should be irrigated, debrided, and elevated. Dural tears should be repaired. Expedient management is necessary to prevent meningitis and its associated sequelae.

Soft-tissue reconstruction for recalcitrant diabetic foot wounds.

Thirty-three consecutive patients with plantar soft-tissue defects were managed by a single surgeon (EDN) with reconstruction by a medial plantar artery (MPA)-based flap. Foot defects resulted from a combination of abnormal weightbearing distribution and neuropathy secondary to diabetes mellitus in all patients. A retrospective study of diabetic patients from 1984 to 1997 with foot defects reconstructed with a MPA-based flap were reviewed. Thirty-three patients (age 55 +/- 9) with an average tissue deficit of 13 +/- 9 cm2 had MPA reconstruction of the heel (n = 8), midfoot (n = 23), and forefoot (n = 2). The mean follow-up was 19 months (range, 3 months-5 years). There were four minor complications, including marginal flap necrosis or localized infection, although all healed uneventfully. There were six major complications resulting in loss of the flap and proximal amputation. Out of seven patients, there were 12 rerotations of the previously rotated flap. Various techniques for reconstruction of plantar foot defects have been described in the literature. Utilizing glabrous skin for reconstruction of these defects is appealing for its unique shear and pressure-resisting properties. Surgical management of diabetic foot defects with the medial plantar artery flap is an effective means of soft tissue reconstruction.

Determining duration of antibiotic use in children with complicated appendicitis.

BACKGROUND: The introduction of broad spectrum antibiotics has substantially decreased rates of mortality and morbidity associated with complicated appendicitis in children. The generally recommended therapy for children with complicated (gangrenous or perforated) appendicitis is administration of postoperative antibiotics for 3 to 14 days, but the decision as to the specific duration of treatment lies with the treating physician. AIM: This study evaluates whether the recommendation that the combination of the patient's being afebrile and eating and having a normal white blood cell (WBC) count and < or = 3% band forms can be used to decide when sufficient antibiotics have been given and can be safely discontinued. METHODS: Thirty-three consecutive patients seen in the pediatric surgical service with perforated or gangrenous appendicitis were studied prospectively. All patients received a standard protocol of resuscitation, appendectomy and broad spectrum antimicrobial therapy to be continued until they were eating, afebrile and had normal white blood cell counts with < or = 3% immature neutrophils (band forms). RESULTS: Thirty-two children were treated until they met all criteria when antibiotics were stopped and the patients were discharged. Of these patients 31 had unremarkable courses of recovery with no development of intraabdominal abscess or wound infection [predictive value of criteria, 97% (31 of 32)]. The remaining patient who met the criteria required rehospitalization for treatment of intraabdominal abscess. Another patient was discharged prematurely when he failed to meet the criterion of afebrility. Although he was eating and his WBC count was normal, he had a temperature of 38.5 degrees C during the 24 h before discharge. He was readmitted for surgical drainage of an intraabdominal abscess, yielding a 100% predictive value for the criterion mismatch (1 of 1). CONCLUSION: Based on our observations, when a patient with complicated appendicitis is afebrile for 24 h (temperature < 38 degrees C), is eating and has a WBC count with < or = 3% band forms, antibiotics can be safely discontinued with small risk of recurrent intraabdominal abscess.

Endometrioma of the abdominal wall following combined abdominoplasty and hysterectomy: case report and review of the literature.

An unusual case is reported of abdominal wall endometrioma presenting in a lower abdominal scar following a combined hysterectomy and abdominoplasty performed 5 years earlier. Current diagnostic methods and recommended surgical management are outlined.

Mycotic infection with mucormycosis.

Mucormycosis comprises infections caused by fungi in the class Zygomycetes (order Mucorales). Clinical infections usually manifest as nasopharyngeal, cutaneous, pulmonary, or disseminated disease. Generally, the infection is found only in immunocompromised hosts. The underlying immunologic defects that are responsible for predisposing different populations of patients to the development of mucormycosis are not well understood. This article retrospectively reviews the experience at the Medical Center of Delaware with this relatively rare fungal infection.

Adequacy and efficacy of lateral cervical spine radiography in alert, high-risk blunt trauma patient.

OBJECTIVE: The purpose of this study was to determine the adequacy and accuracy of lateral cervical spine radiographs in the initial evaluation of alert, high-risk trauma patients evaluated at a Level I trauma center. METHODS: Data were obtained retrospectively through review of trauma service admissions from January 1, 1994, to July 31, 1995. Included were all patients triaged to a trauma response team with age > 15 years, Glasgow Coma Scale score > 13, and blunt mechanism of injury. Lateral cervical spine radiograms were obtained routinely before secondary survey and were reviewed for technical adequacy (all seven cervical vertebrae, C7/T1 interspace). The presence of cervical symptoms (pain, tenderness, neurologic deficits) was recorded. Sensitivity and specificity were calculated for lateral cervical spine radiography and cervical symptoms in predicting the presence of cervical spine injury. Bayesian analysis, which allows for the current probability of occurrence to be factored by previously reported probabilities of occurrence, was used to determine the negative predictive probability of lateral cervical spine radiography and absence of cervical symptoms to predict the absence of injury to the cervical spine. RESULTS: Three hundred fifty-three patients received lateral cervical spine radiograms, of which 223 (63%) were determined to be adequate for interpretation. Cervical symptoms were present in 77 patients (20%). Only 32 (42%) of this group's lateral cervical spine radiograms were adequate. Nine patients (2.4%) had acutely fractured cervical vertebrae or ligamentous disruption. Lateral cervical spine radiography showed the injury in only six of these patients. The sensitivity, specificity, and negative predictive probability for lateral cervical spine radiography were 67, 58, and 1.4%, respectively, and for absence of cervical symptoms, 89, 81, and 0.32%, respectively. CONCLUSION: The higher accuracy and lower negative predictive probability make the absence of cervical symptoms in the alert, high-risk, blunt trauma patient a better screening test than lateral cervical spine radiography. We suggest that lateral cervical spine radiography is not needed in the initial evaluation of alert patients who have sustained blunt trauma.

The role of nitric oxide in subcutaneous and transmural gut tissue oxygenation.

The influence of inhibiting the nitric oxide (NO) synthetase on tissue perfusion as indicated by tissue oxygen tensions was determined. Tissue oxygen probes were placed subcutaneously and on serosal and mucosal surfaces of colon of anesthetized adult rats. After a control period, the inhibitor of NO formation, N(G)-nitro-L-arginine methyl ester (L-NMMA), was given intravenously and followed 20 min later by infusion of substrate for NO synthetase, L-arginine. Mean arterial blood pressure (MAP), subcutaneous tissue oxygen tension (P(SQ)O2), serosal tissue oxygen tension (P SO(2)), and mucosal tissue oxygen tension (P(M)O2) were simultaneously measured. Baseline values for the measured parameters were MAP = 95 + or - 9 mmHg, P(SQ)O2 = 61 + or - 7 mmHg, P(S)O2 65 + or - 7 mmHg, and P(M)02 = 9 + or - 2 mmHg. The infusion of L-NMMA induced a significant increase in MAP to 123 + or - 7 mmHg (p < .001) and P(SQ)O2 to 72 + or - 7 mmHg (p < .001). P(S)O2 did not change significantly from baseline after L-NMMA infusion. A significant decrease in P(M)O2 to 4 + or - 2 mmHg was noted after L-NMMA infusion (p < .001). The administration of L-arginine promptly returned all measured parameters to baseline levels within 10 min of infusion. A transmural P(O2) gradient exists across the colon with P(M)O2 far lower than P(S)O2. P(SQ)O2 approximates P(S)O2 at baseline and P(S)O2 is not altered by inhibition of the NO synthetase. The 45% reduction in mucosal PO2 after L-NMMA, which was reversed by L-arginine infusion, suggests that nitric oxide participates in splanchnic vasomotor control with a preferential effect in the mucosal vasculature. The observed decrease in mucosal PO2 observed after inhibition of NO production is similar to the worsened hypoxia previously measured during hemorrhagic shock. Further work clarifying the local control mechanisms of gut tissue P02 can direct therapies to increase gut tissue oxygenation.

Lactate stimulation of macrophage-derived angiogenic activity is associated with inhibition of Poly(ADP-ribose) synthesis.

Injury and inflammation lead to hypoxia and elevated lactate in wounds. This redox environment establishes cells in a reparative phenotype and leads macrophages to release angiogenic substances by unclear mechanisms. We investigated compounds known to modulate polyadenosine diphophoribose (pADP-R) levels in their effect on macrophage-derived angiogenic activity. Macrophages cultured from rabbit bone marrow were exposed to lactate, nicotinamide, and/or beta-nicotinamide adenine dinucleotide (NAD+). Supernatants were assayed for angiogenesis, and macrophages were analyzed for NAD+ content, poly(ADP-ribose) synthetase activity, and total (ADP-ribose)n synthesis. Lactate-, nicotinamide-, and lactate and nicotinamide-treated macrophages elicited significantly increased angiogenic activity compared with control or NAD+-treated cells. Lactate treatment decreased NAD+ content by 42 +/- 4% and (ADP-ribose)n synthesis by 37 +/- 5%. Nicotinamide reduced poly(ADP-ribose) synthetase activity and poly(ADP-ribose) synthesis. Thus, macrophage-derived angiogenic activity may be mediated by the redox environment involving NAD+ metabolites.

Transmural gut oxygen gradients in shocked rats resuscitated with heparan.

OBJECTIVES: To develop a reproducible model to measure transmural gut tissue PO2, to determine the gradient from serosa to mucosa during normovolemia and hypovolemia, and to determine the effect of resuscitation with heparan sulfate (danaparoid sodium) on this gradient. DESIGN: Fluorescent tissue oxygen sensors were placed onto serosal and mucosal surfaces of rat colon. Hemorrhagic shock was induced using a fixed pressure (mean arterial pressure, 40 mm Hg) model and resuscitated with either saline solution or heparan. RESULTS: Control animals had stable mean (+/- SD) serosal and mucosal tissue oxygen tensions (PO2) of 64 +/- 4 and 10 +/- 2 mm Hg, respectively. In shocked animals, baseline serosal PO2 decreased to 37 +/- 2 mm Hg at a mean (+/- SD) of 19 +/- 7 minutes after the initiation of hemorrhage. Mucosal values decreased to a minimum of 4 +/- 2 mm Hg at 45 +/- 15 minutes after the initiation of hemorrhage. Serosal PO2 returned to baseline during resuscitation in both control and heparan-resuscitated animals. Mucosal PO2 did not return to baseline in the shock/no heparan group. In the heparan-resuscitated animals, however, mucosal PO2 increased above baseline (13 +/- 3 mm Hg at 3 hours after completion of hemorrhage). CONCLUSIONS: A transmural gradient of PO2 exists across the colon with mucosal PO2 far lower than serosal PO2. Both serosal and mucosal PO2 decrease during hypovolemia. During hypovolemia, the PO2 of the entire gut wall is in a range in which phagocytic killing is impaired by hypoxia. Heparan improved mucosal PO2 and it may restore and/or protect gut function by oxygen-related mechanisms.

AES analysis of stainless steel corroded in saline, in serum and in vivo.

Auger electron spectroscopic (AES) studies were conducted to examine the surface film of stainless steel specimens which had been subjected to passive and anodic corrosion in vitro and in vivo. Anodic corrosion was accelerated by the application of a +500 mV (SCE) potential for 30 minutes. Experiments performed in 0.9% saline indicated little alteration in the nature of the surface film compared to a freshly prepared control specimen. Auger analysis of specimens in 10% serum or in vivo revealed that passive film thickness was dependent on the corrosive environment. The films of specimens immersed under freely corroding conditions in 10% serum or in vivo were similar to the control film. Accelerated corrosion performed in 10% calf serum resulted in significant film thickening. The thickest films were from accelerated corrosion in vivo. The mechanism for the altered surface films produced by corrosion in vivo or in serum as compared to saline needs to be investigated further.